The present invention relates generally to a method of grounding and more particularly to a method of electrical grounding for use in spacecraft design.
Satellites and other spacecraft are known to experience geomagnetic substorms and similar phenomenon while in space. These phenomena can impart large negative electrical potentials to isolated metal components on the spacecraft. When large potential differences are present between components on the spacecraft, electrostatic discharges are known to occur.
Electrostatic discharges within the spacecraft are highly undesirable and can pose hazards to the operation and performance of the spacecraft. It is known that electrostatic discharges have caused permanent electrical degradation to solar arrays when in orbit. The electrostatic discharges are also known to create high density plasma which can create temporary electrical paths between solar cells. These temporary electrical paths are known to result in localized heating and electrical shorts. Even when electrostatic discharges do not damage the spacecraft, their presence can interfere with spacecraft performance. The costs involved in spacecraft design, production, and launch make the presence of such electrostatic discharges and their resulting effects on the spacecraft unacceptable.
It is known that electrostatic discharges can be minimized in spacecraft by grounding all isolated metal surfaces to the spacecraft electrical system ground. However, grounding each isolated metal surface to the spacecraft electrical system ground can add undesirable weight and cost to the design of the spacecraft. In addition, the area within the spacecraft is often limited and may make the grounding of some components unfeasible. Furthermore, present designs and components often cannot be retrofitted to accomplish such a grounding procedure.
There is, therefore, a need for a method of reducing electrostatic discharges in isolated metal components without the need to attach such components to the spacecraft electrical system ground.
It is therefore an object of the present invention to provide an improved grounding method for use in a spacecraft that reduces the electrostatic discharge in isolated conductive components without the need to electrically attach such components to the spacecraft electrical system ground.
In accordance with the objects of the present invention, an electrical ground for use in a spacecraft is provided. The electrical ground utilizes a first surface, exposed to sunlight. The first surface is capable of emitting electrons by photoemission when exposed to sunlight. Isolated conductive surfaces are in electrical communication with the first surface through the use of conductive connectors that allow electric charge to flow from the isolated conductive surfaces to the first surface, where the charge may be dispersed by photoemission.